events件你也可以使用它來(lái)自定義

Doctrine2featuresalightweighteventsystemthatispartoftheCommonpackage.Doctrineusesittodispatchsystemevents,mainlylifecycleevents.YoucanalsouseitforyourowncustomTheEventTheeventsystemiscontrolledbytheEventManager.ItisthecentralpointofDoctrine’seventlistenersystem.Listenersareregisteredonthemanagerandeventsaredispatchedthroughthemanager.9.9.1系$evm=newNowwecanaddsomeeventlistenerstothe$evm.Let’screateaTestEventclasstoyaroundclass{constpreFoo='preFoo';constpostFoo='postFoo';privatepublic$preFooInvoked=false;public {$evm->addEventListener(array(self::preFoo,self::postFoo),}publicfunctionpreFoo(EventArgs{$this->preFooInvoked=}publicfunctionpostFoo(EventArgs{$this->postFooInvoked=}}//Createanew$test=newEventscanbedispatchedbyusingthedispatchEvent()$evm-$evm-$evm->removeEventListener(array(self::preFoo,self::postFoo),TheDoctrine2eventsystemalsohasasimpleconceptofeventsubscribers.WecandefineimplementsagetSubscribedEvents()methodwhichreturnsanarrayofeventsitshouldbesubscribedto.Doctrne2系統(tǒng)也有一個(gè)簡(jiǎn)單的時(shí)間訂閱的概念。我們可以定義一個(gè)簡(jiǎn)單的esEvenSuscriber類，它實(shí)現(xiàn)自DocrneComonvenubscrber接口，并且實(shí)現(xiàn)一個(gè)getubsrbedEvent()方法，此方法返回一個(gè)應(yīng)該被訂閱的的數(shù)組。classTestEventSubscriberimplements{public$preFooInvoked=publicfunction{$this->preFooInvoked=}publicfunction{return}}$eventSubscriber=new$evm-TheThearraytoreturninthegetSubscribedEventsmethodisasimplearraywiththevaluestheeventnames.Thesubscribermusthaveamethodthatisnamedexactlylikethe Nowwhenyoudispatchanevent,anyeventsubscriberswillbenotifiedforthat$evm-Nowyoucantestthe$eventSubscriberinstancetoseeifthepreFoo()methodwasif($eventSubscriber-{echo'prefoo}NamingEventsbeingusedwiththeDoctrine2EventManagerarebestnamedwithcamelcaseandthevalueofthecorrespondingconstantshouldbethenameoftheconstantitself,evenwithspelling.Thishasseveralreasons:Itiseasytoread.EachmethodwithinanEventSubscriberisnamedafterthecorrespondingconstant’svalue.Iftheconstant’snameandvaluedifferitcontradictstheintentionofusingtheconstantandmakesyourcodehardertomaintain.AnexampleforacorrectnotationcanbefoundintheexampleTestEventLifecycleTheEntityManagerandUnitOfWorktriggerabunchofeventsduringthelife-timeoftheirregisteredpreRemove-ThepreRemoveeventoccursforagivenentitybeforetherespectiveEntityManagerremoveoperationforthatentityisexecuted.ItisnotcalledforaDQLDELETEstatement.postRemove-ThepostRemoveeventoccursforanentityaftertheentityhasbeendeleted.Itwillbeinvokedafterthedatabasedeleteoperations.ItisnotcalledforaDQLDELETEstatement.prePersist-TheprePersisteventoccursforagivenentitybeforetherespectivepersistoperationforthatentityisexecuted.Itshouldbenotedthatthiseventisonlytriggeredoninitialpersistofanentity(i.e.itdoesnottriggeronfutureupdates).postPersist-ThepostPersisteventoccursforanentityaftertheentityhasbeenmadepersistent.Itwillbeinvokedafterthedatabaseinsertoperations.GeneratedprimarykeyvaluesareavailableinthepostPersistevent.preUpdate-ThepreUpdateeventoccursbeforethedatabaseupdateoperationstoentitydata.ItisnotcalledforaDQLUPDATEstatement.postUpdate-ThepostUpdateeventoccursafterthedatabaseupdateoperationstoentitydata.ItisnotcalledforaDQLUPDATEstatement.postLoad-ThepostLoadeventoccursforanentityaftertheentityhasbeenloadedintothecurrentEntityManagerfromthedatabaseoraftertherefreshoperationhasbeenappliedtoit.loadClassMetadata-TheloadClassMetadataeventoccursafterthemapmetadataforaclasshasbeenloadedfromamapsource(annotations/xml/yaml).ThiseventisnotalifecycleonClassMetadataNotFound-Loadingclassmetadataforaparticularrequestedclassnamefailed.Manipulatingthegiveneventargsinstanceallowsprovidingfallbackmetadataevenwhennoactualmetadataexistsorcouldbefound.Thiseventisnotalifecyclecallback.preFlush-ThepreFlusheventoccursattheverybeginningofaflushoperation.Thiseventisnotalifecyclecallback.onFlush-TheonFlusheventoccursafterthechange-setsofallmanagedentitiesarecomputed.Thiseventisnotalifecyclecallback.postFlush-ThepostFlusheventoccursattheendofaflushoperation.Thiseventisnotalifecyclecallback.onClear-TheonCleareventoccurswhentheEntityManager#clear()operationisinvoked,afterallreferencestoentitieshavebeenremovedfromtheunitofwork.ThiseventisnotalifecyclepreFlush- onFlush-onFlush postFlush- onClear-onClear yafterobjectsarebeinghydrated,andthereforeassociationsarenotguaranteedtobeinitialized.Itisnotsafetocombineusageof 注意，當(dāng)使用te(),postLoadNotethatthepostRemoveeventoranyeventstriggeredafteranentityremovalcanreceivean incaseyouhaveconfiguredanentitytocascaderemoveInthiscase,youshouldloadyourself intheassociatedpre .YoucanaccesstheEventconstantsfromtheEventsclassintheORMechoEvents::preUpdate;ThesecanbehookedintobytwodifferenttypesofeventLifecycleCallbacksaremethodsontheentityclassesthatarecalledwhentheeventistriggered.Asofv2.4theyreceivesomekindofEventArgsinstance.LifecycleEventListenersandSubscribersareclasseswithspecificcallbackmethodsthatTheEventArgsinstancereceivedbythelistenergivesaccesstotheentity,EntityManagerand AllAllLifecycleeventsthathappenduringtheflush()ofanEntityManagerhaveveryconstraintsontheallowedoperationsthatcanbeexecuted.PleasereadtheImplementingEventListenerssectionverycarefullytounderstandwhichoperationsareallowedinlifecycle限定條件。閱讀ImplementingEventListenersLifecycleLifecycleCallbacksaredefinedonanentityclass.Theyallowyoutotriggercallbackswheneveraninstanceofthatentityclassexperiencesarelevantlifecycleevent.Morethanonecallbackcanbedefinedforeachlifecycleevent.LifecycleCallbacksarebestusedforsimpleoperationsspecifictoaparticularentityclass’slifecycle.classUser{//*@Column(type="string",publicprivate$createdAt;/**@PrePersistpublicfunction{$this->createdAt=date('Y-m-d}/**@PrePersistpublicfunction{$this->value='changedfromprePersist}/**@PostPersistpublicfunction{$this->value='changedfrompostPersist}/**@PostLoadpublicfunction{$this->value='changedfrompostLoad}/**@PreUpdatepublicfunction{$this->value='changedfrompreUpdate}}Notethatthemethodssetaslifecyclecallbacksneedtobepublicand,whenusingtheseannotations,youhavetoapplythe@HasLifecycleCallbacksmarkerannotationontheentityclass.IfyouwanttoregisterlifecyclecallbacksfromYAMLorXMLyoucandoitwiththetype:#type:string(50)prePersist:[doStuffOnPrePersist,doOtherStuffOnPrePersist]postPersist:[doStuffOnPostPersist]InYAMLthekeyofthelifecycleCallbacksentryistheeventthatyouaretriggeringonandthevalueisthemethod(ormethods)tocall.TheallowedeventtypesaretheoneslistedinthepreviousLifecycleEventssection.XMLwouldlooksomethinglike<?xmlversion="1.0"encoding="UTF-<doctrine-mapxmlns="xmlns:xsi="/Users/robo/dev/php/Doctrine/doctrine-map<entity<lifecycle-<lifecycle-callbacktype="prePersist"<lifecycle-callbacktype="postPersist"</lifecycle-</doctrine-mapInXMLthetypeofthelifecycle-callbackentryistheeventthatyouaretriggeringonandthemethodisthemethodtocall.TheallowedeventtypesaretheoneslistedinthepreviousLifecycleEventsWhenusingYAMLorXMLyouneedtoremembertocreatepublicmethodstomatchthecallbacknamesyouneedtobedefinedonyourUsermodel.//class{//publicfunction{//}publicfunction{//}publicfunction{//}}LifecycleCallbacksEventNewinversionSince2.4thetriggeredeventisgiventothelifecycle-//class{publicfunctionpreUpdate(PreUpdateEventArgs{ ($event- //Dosomethingwhentheusernameis}}}ListeningandsubscribingtoLifecycleLifecycleeventlistenersaremuchmorepowerfulthanthesimplelifecyclecallbacksthataredefinedontheentityclasses.Theysitatalevelabovetheentitiesandallowyoutoimplementre-usablebehaviorsacrossdifferententityclasses.NotethattheyrequiremuchmoredetailedknowledgeabouttheinnerworkingsoftheEntityManagerandUnitOfWork.PleasereadtheImplementingEventListenerssectioncarefullyifyouaretryingtowriteyourownlistener.Foreventsubscribers,therearenosurprises.TheydeclarethelifecycleeventstheirgetSubscribedEventsmethodandprovidepublicmethodsthatexpecttherelevantarguments.Alifecycleeventlistenerlookslikethefollowing:ImplementingEventListenersuseclass{publicfunctionpreUpdate(LifecycleEventArgs{$entity=$args-$entityManager=$args-//perhapsyouonlywanttoactonsome"Product"entityif($entityinstanceofProduct){//dosomethingwiththe}}}AlifecycleeventsubscribermaylookslikeuseuseuseclassMyEventSubscriberimplements{publicfunction{array(Events::postUpd}publicfunctionpostUpdate(LifecycleEventArgs{$entity=$args-$entityManager=$args-//perhapsyouonlywanttoactonsome"Product"entityif($entityinstanceofProduct){//dosomethingwiththe}}LifecycleLifecycleeventsaretriggeredforallentities.Itistheresponsibilityofthelistenersandsubscriberstocheckiftheentityisofatypeitwantstohandle. Toregisteraneventlistenerorsubscriber,youhavetohookitintotheEventManagerthatispassedtotheEntityManagerfactory:$eventManager=new$eventManager->addEventListener(array(Events::preUpdate),new$eventManager->addEventSubscriber(new$entityManager=EntityManager::create($dbOpts,$config,YoucanalsoretrievetheeventmanagerinstanceaftertheEntityManagerwas$entityManager->getEventManager()->addEventListener(array(Events::preUpdate),new$entityManager->getEventManager()->addEventSubscriber(newImplementingEventThissectionexinswhatisandwhatisnotallowedduringspecificlifecycleeventsoftheUnitOfWork.AlthoughyougetpassedtheEntityManagerinalloftheseevents,youhavetofollowtheserestrictionsverycarefullysinceoperationsinthewrongeventmayproducelotsofdifferenterrors,suchasinconsistentdataandlostupdates/persists/removes.Forthedescribedeventsthatarealsolifecyclecallbackeventstherestrictionsapplyaswell,withtheadditionalrestrictionthat(priortoversion2.4)youdonothaveaccesstotheEntityManagerorUnitOfWorkAPIsinsidetheseevents.TherearetwowaysfortheprePersisteventtobetriggered.OneisobviouslywhenyoucallEntityManager#persist().Theeventisalsocalledforallcascadedassociations.ThereisanotherwayforprePersisttobecalled,insidetheflush()methodwhenchangestoassociationsarecomputedandthisassociationismarkedascascadepersist.AnynewentityfoundduringthisoperationisalsopersistedandprePersistcalledonit.Thisiscalled“persistencebyreachability”.InbothcasesyougetpassedaLifecycleEventArgsinstancewhichhasaccesstotheentityandtheentityThefollowingrestrictionsapplytoIfyouareusingaPrePersistIdentityGeneratorsuchassequencestheIDvaluewillNOTbeavailablewithinanyPrePersistevents.DoctrinewillnotrecognizechangesmadetorelationsinaprePersistevent.Thisincludesmodificationstocollectionssuchasadditions,removalsorrecement.ThepreRemoveeventiscalledoneveryentitywhenitspassedtotheEntityManager#remove()method.Itiscascadedforallassociationsthataremarkedascascadedelete.TherearenorestrictionstowhatmethodscanbecalledinsidethepreRemoveevent,exceptwhentheremovemethoditselfwascalledduringaflushoperation.insideitslisteners.classPreFlushExampleListener{publicfunctionpreFlush(PreFlushEventArgs{//}}OnFlushisaverypowerfulevent.ItiscalledinsideEntityManager#flush()afterthechangestoallthemanagedentitiesandtheirassociationshavebeencomputed.Thismeans,theonFlusheventhasaccesstothesetsof:EntitiesscheduledforinsertEntitiesscheduledforupdateEntitiesscheduledforremovalCollectionsscheduledforupdateCollectionsscheduledforremovalTomakeuseoftheonFlusheventyouhavetobefamiliarwiththeinternalUnitOfWorkAPI,whichgrantsyouaccesstothepreviouslymentionedsets.Seethisexample: class{publicfunctiononFlush(OnFlushEventArgs{$em=$eventArgs-$uow=$em-foreach($uow->getScheduledEntityInsertions()as$entity)}foreach($uow->getScheduledEntityUpdates()as$entity)}foreach($uow->getScheduledEntityDeletions()as$entity)}foreach($uow->getScheduledCollectionDeletions()as$col)}foreach($uow->getScheduledCollectionUpdates()as$col)}}}ThefollowingrestrictionsapplytotheonFlushIfyoucreateandpersistanewentityinonFlush,thencallingEntityManager#persist()isnotenough.Youhavetoexecuteanadditionalcallto$unitOfWork->computeChangeSet($classMetadata,$entity).Changingprimitivefieldsorassociationsrequiresyoutoexplicitlytriggera putationofthechangesetoftheaffectedentity.Thiscanbedonebycalling$unitOfWork- 的調(diào)用$unitOfWork->computChangeSet($classMetadata,$entity) itslisteners.classPostFlushExampleListener{publicfunctionpostFlush(PostFlushEventArgs{//}}PreUpdateisthemostrestrictivetouseevent,sinceitiscalledrightbeforeanupdatestatementiscalledforanentityinsidetheEntityManager#flush()method.Changestoassociationsoftheupdatedentityareneverallowedinthisevent,sinceDoctrineguaranteetocorrectlyhandlereferentialintegrityatthispointoftheflushoperation.Thiseventhasapowerfulfeaturehowever,itisexecutedwithaPreUpdateEventArgsinstance,whichcontainsareferencetothecomputedchange-setofthisentity.Thismeansyouhaveaccesstoallthefieldsthathavechangedforthisentitywiththeiroldandnewvalue.ThefollowingmethodsareavailableonthePreUpdateEventArgs:getEntity()togetaccesstotheactualgetEntityChangeSet()togetacopyofthechangesetarray.Changestothisreturnedarraydonotaffectupdating.getOldValue($fieldName)andgetNewValue($fieldName)toaccessthevaluesofafield.setNewValue($fieldName,$value)tochangethevalueofafieldtobeupdated.Asimpleexampleforthiseventlooks()hasChangedField($fieldName)檢查是否當(dāng)前實(shí)體的給定字段名修改了。getOldValue($fieldName)和getNewValue($fieldName)來(lái)進(jìn)入一個(gè)字段的值。setNewValue($fieldName,$value)來(lái)修改用來(lái)更新字段的值。class{publicfunctionpreUpdate(PreUpdateEventArgs{if($eventArgs->getEntity()instanceofUser)if($eventArgs->hasChangedField('name')&&$eventArgs->getNewValue('name')=='Alice')$eventArgs->setNewValue('name',}}}}Youcouldalsousethislistenertoimplementvalidationofallthefieldsthathavechanged.Thisismoreefficientthanusingalifecyclecallbackwhenthereareexpensivevalidationstocall:class{publicfunctionpreUpdate(PreUpdateEventArgs{if($eventArgs->getEntity()instanceofAccount) $this->validateCreditCard($eventArgs-}}}privatefunction{//throwanexceptiontointerruptflushevent.Transactionwillberolled}}RestrictionsforthisChangestoassociationsofthepassedentitiesarenotrecognizedbytheflushoperationanymore.Changestofieldsofthepassedentitiesarenotrecognizedbytheflushoperationanymore,usethecomputedchange-setpassedtotheeventtomodifyprimitivefieldvalues,e.g.use$eventArgs-AnycallstoEntityManager#persist()orEntityManager#remove(),evenincombinationwithUnitOfWorkAPIarestronglydiscouragedanddon’tworkasexpectedoutsidetheflush,)?postUpdate,postRemove,ThethreeposteventsarecalledinsideEntityManager#flush().Changesinherearenotrelevanttothepersistenceinthedatabase,butyoucanusetheseeventstoalternon-persistableitems,likenon-mappedfields,loggingorevenassociatedclassesthataredirectlymappedbyDoctrine.ThiseventiscalledafteranentityisconstructedbytheEntityNewinversionAnentitylistenerisalifecyclelistenerclassusedforanTheentitylistener’smapmaybeappliedtoanentityclassormappedAnentitylistenerisdefinedbymaptheentityclasswiththecorrespondingmap2.4 namespace/**@Entity@EntityListeners({"UserListener"})classUser{ EntitylistenersAnEntityListenercouldbeanyclass,bydefaultitshouldbeaclasswithano-argDifferentfromImplementingEventListenersanEntityListenerisinvokedjusttothespecifiedAnentitylistenermethodreceivestwoarguments,theentityinstanceandthelifecycleevent.Thecallbackmethodcanbedefinedbynamingconventionorspecifyingamethodmap.Whenalistenermapisnotgiventheparserwillusethenamingconventiontolookforamatchingmethod,e.g.itwilllookforapublicpreUpdate()methodifyouarelisteningtothepreUpdateWhenalistenermapisgiventheparserwillnotlookforanymethodsusingthe 當(dāng)一 preUpdate，它將找一個(gè)publicpreUpdate()當(dāng)一 class{publicfunctionpreUpdate(User$user,PreUpdateEventArgs{//Dosomethingonpre}}Todefineaspecificeventlistenermethod(onethatdoesnotfollowthenamingconvention)youneedtomapthelistenermethodusingtheeventtypemap:class{/**@PrePersistpublicfunctionprePersistHandler(User$user,LifecycleEventArgs$event){//.../**@PostPersistpublicfunctionpostPersistHandler(User$user,LifecycleEventArgs$event){//.../**@PreUpdatepublicfunctionpreUpdateHandler(User$user,PreUpdateEventArgs$event){//.../**@PostUpdatepublicfunctionpostUpdateHandler(User$us